#define _CRT_SECURE_NO_WARNINGS
#pragma warning(disable : 4996)
#pragma warning(disable : 6031)

#include <stdio.h>

float max3(int a, int b, int c)
{
    float max = 0;
    max = a > b ? (float)a : (float)b;
    max = max > c ? max : (float)c;
    return max;
}

int main() {
    int a = 0, b = 0 , c = 0 ;
    float m = 0;
    scanf("%d %d %d", &a, &b, &c);
    m = max3(a + b, b, c) / (max3(a, b + c, c) + max3(a, b, b + c));
    printf("%.2f", m);
    return 0;
}